1. Field of the Invention
This invention relates to a single pull-cord controller of roman shade, more particularly to a novel pull-cord controller having safety precaution in which a single pull-cord can be wound for storage without being exposed outside too long so as to achieve the purpose of strangulation prevention.
2. Brief Description of the Prior Art
Conventional window curtains have a variety of options depending on its use, such as traditional fabric curtains, roller blinds, roman shade and window blinds. Regardless of the type of window curtains, the difference between the size and length do exist among them, so that the length of each window curtains can match the window frame so as to achieve perfect shielding effect.
The roman shade (also called roman blinds, pleated blinds or horizontal blinds) is developed by the curtain industries, in which a rolling fabric or a curtain body made by the other material is driven by controlling the winding and unwinding of a drawstrings with a curtain top-mandrel unit, so as to form pleated, waves, or flat folding pattern. Generally, the drawstring is connected to the lower portion of the curtain body. When the curtain body is to be rolled up, the drawstring is wound up so as to initiate the rolling up of the curtain body from the lower portion thereof. However, the controller for controlling the up-down of the curtain body includes a bead chain unit having a bead chain rope; the bead chain unit can drive a reel for winding the drawstring. When the bead chain rope enabling dual direction control is pulled, the bead chain unit can drive a reel to wind or unwind the drawstring so as to achieve up-down of the curtain. This type of structure can be seen in a Taiwanese Patent Gazette No. M290529 entitled “Bead Chain Control Unit Structure of Window Curtain” opened to public on May 11, 2006, a Taiwanese Patent Gazette No. M 261586 entitled “Bead Chain Control Unit Structure of Pleated Curtain” opened to public on Apr. 11, 2005, and a Taiwanese Patent Gazette No. M420276 entitled “Controller Structure of Roman Shade” opened to public on Jan. 11, 2012.
The conventional roman shade has a looped bead chain rope (pull-cord) to control bi-directional action of folding and unfolding of the curtain body. Depending on the window frame on site, the length of the looped bead chain rope is tailored to fit the total installation. If there is no suitable holder to fix the looped bead chain rope, it is often got entangled easily. In more serious condition, if the looped bead chain rope is played by ignorant children, it is easily got tying around children's body or neck and it is often difficult for children to get rid of it and hence hazard may occur. Therefore, this is the problem the concerned industries strongly want to improve.
In view of the above problem, the inventor of the present invention hereby proposes a single pull-cord controller of roman shade according to the improvement conducted on the disadvantages of prior art and based on his abundant experience in product development and manufacturing in relevant field, so as to achieve better practical value.